Rock drilling device



March 22, 1955 w. BANCK EI'AL 2,704,654

ROCK DRILLING DEVICE Filed March 11, 1952 :s Sheets-Sheet 1 INVf/VfdkdUM M W I QM W mwz.

March 22, 1955 W. BANCK ETAL ROCK DRILLING DEVICE 3 Sheets-Sheet 2 FiledMarch 11. 41952 March 22, 1955 w. BANCK ETAL 2,704,654

ROCK DRILLING DEVICE Filed March 11, 1952 3 Sheets-Sheet 3 United StatesPatentO ROCK DRILLING DEVICE Werner Banck, Stuttgart, Ottmar Baur,Wendlingen, Karl Hiigele, Stuttgart-Wangen, and Wendel Rolli, Stuttgart-.Degerloch, Germany, assignors to Robert Bosch G. m.

b. H., Stuttgart, Germany Application March 11, 1952, Serial No. 275,962

Claims priority, application Germany March 24, 1951 3 Claims. (Cl.25545) The invention concerns a rock drilling device having a drillwhich is displaceable, along a girder-like support through hydraulicpressure. Drilling devices are known in which a cylinder, extending inthe direction of drilling, is located wholly or substantially whollybehind the drill and with its. hydraulically actuated piston leads thedrill forwardly on a girder which is not directly connected with thecylinder and which consists of two sliding guides. This arrangementnecessitates a construction of considerable overall length and weight,since the girder and the means for advancing the drill must be securedseparately and must be able to withstand various loads. In addition thedrill advancing means of the known arrangement is largely exposed to therock dust.

According to this invention, the girder-like support of the drillconsists of a hollow body or tubular member which houses in its interiora piston and cylinder assembly adapted to be connected to the source ofpressure and, by means of intermediate connecting means, to advance thedrilling machine along the hollow support.

According to another aspect of this invention, a rock drilling deviceconsists of a girder-like support in the form of a hollow body ortubular member, a drilling machine slidably mounted in the hollow bodyor tubular member, a .cylinder housed within the hollow body or tubularmember for connection with a source of fluid pressure, a piston in thecylinder, and intermediate means connecting the piston and drillingmachine and adapted to enable the piston to displace the drillingmachine along the hollow body or tubular member for advancing thedrilling machine when the fluid pressure is supplied to the cylinder.

This arrangement enables the drill advancing means to be largelyprotected from rock dust and other foreign matter, whilst ,the overalllength of the drilling device can be made to conform approximately tothat of the depth of the bore hole at least, but in any case is muchshorter than that of the known type. In addition a rock drilling deviceaccording to this invention possesses sufiicient stability althoughbeing relatively light in weight.

The invention is further described with reference to the accompanyingdrawings in which illustrate two embodiments of the invention by way ofexamples only and in which:

Fig. 1 is a side elevation partly in section, and Fig. 2 a correspondingend view of the first embodiment,

Fig. 3 is a side elevation also partly in section of the secondembodiment,

Fig. 4 is a diagrammatic view of the connections to the valve; and

Fig. 5 is a side elevational view partly in section of the pump, motorand governor which produces the pressure to advance the drillingmachine. 1

Referring first to Figs. 1 and 2 of the drawings, a tubular support 1has two slide guides 2 welded thereon which support and guide a slide 3onwhich an electric drilling machine 4 is mounted. The latter firmlyholds a rock drill 5.

. Disposed in the interior of the tubular support 1 is a cylinder 6, thebase 7 of which is located at the forward end 8 of the tubular support 1facing the bore hole. Displaceably disposed in the cylinder 6 is apiston 9 wherefrom extends a piston rod 10 which carries a reversing orreturn roller or pulley 11 at the end remote from piston 9. A secondreversing or return roller or pulley 12is fitted at the forward end 8 ofthe tubular support 1. One end of a chain 13 is anchored at 14 in theinterior of the tubular support 1. From the anchorage 14 the chainextends rearwardly, around the roller 11 and then forwardly along thelower part of the tubular support 1 to emerge from the end 8 thereof.The chain is then led around the roller 12 and extends rearwardly to theslide 3 and is secured thereto.

The cylinder 6 is approximately half the length of me tubular support 1.A hydraulic pump 16 is mounted at the rear end 15 of the tubularsupport 1. It is driven by an electric motor 17 which is also mounted onthe tubular support 1. On each side of the electric motor 17 there isfitted a fluid tank or reservoir respectively designated 18 and 19.These reservoirs are interconnected by means of pipe lines which areshown in Figures 4 and 5. A pipe 20 (Fig. 2) leads from the reservoir 18to the suction side of the pump 16. From the pressure side of the pump16 a pipe 21 leads to the casing 22 of a rotary control valve which isactuated to change the direction of flow by means of a handle 23. Fromthe valve casing 22 a pipe 24 leads to an intake port 24 in the righthand end of the cylinder 6. This pipe runs lengthwise in the interior ofthe tubular support 1. Additional pipes 25 and 26 lead from the valvecasing 22 to the respective reservoirs 18 and 19. In the position shownon the drawings, the control valve is adapted to connect the pipes 21and 24. When the valve is turned through an angle of the pipes 21 and 26as well as the pipes 24 and 25 are connected to one another. The pump 16contains a governor as will be described. The object of the governor isto maintain the pressure of the fluid supply at a certain value, whichis adjusted by means of a control handle 27 in accordance with thecharacter of stone or rock to be drilled.

It will be obvious that the distance through which the drilling machine4 may be retracted along the hollow member 1 towards its rear end 15will be determined by the effective length of the chain 13. Also, thedrilling machine need not necessarily be secured to the end of the chain13. It may take up a position somewhat forward of the end 15, when inits left end position, depending on the length of the drill 5 in use orwhether the stroke of the drilling machine is required to be long orshort. If the drilling machine is to be anchored to the chain 13 at apoint spaced from its end, then the free or ineffective length of thechain may be rolled up and placed in the base of the drilling machine orin any other convenient position.

The hydraulic operation means and their connections are shown in theFigures 4 and 5. The motor 17 of any suitable and known type turns gears36, 37 to drive shaft 38 of the pump 16. This pump may be constructed inany known manner; by way of example a type similar to usual fuelinjection pumps is shown. A cam 39 fixed to the shaft 38 engages thelower end of a piston 40, which is forced against the cam by a spring41. The upper end of this piston is provided with an oblique controledge 42; which is controlled by a governor described by way of examplein the following.

The piston 40 is guided in the housing 43 of the pump and the cylinder44. A channel 45 connects this cylinder with the suction pipe 20. Theport of this channel leading into the cylinder lies within the range ofstroke of the control edge. Another channel 46 leads from the top ofcylinder 44 to a check valve 47 and the delivery pipe 21.

The piston 40 is provided with a pinion 48, which meshes with a rack 49guided horizontally in the housing 43. At the left end of this rack apiston 50 is slidably arranged in a cylinder 51. The space of thiscylinder on the right side of the piston 50 is separated from theoutside and connected to channel 46 by a passage 52. Against the leftside of the piston 50 presses a spring 53, seated against a plate 54.This plate is fixed to a lever 55, which lever is pivoted at 56 in thehousing 43. The control handle 27 is the head of a screw 57 the tip ofwhich is in contact with the lever 55.

When driven by the motor 17, the piston 40 reciprocates and deliversfluid through the check valve 47 into the pipe 21. The amount ofdelivered fluid depends upon the position of the control edge 42 withrespect to the port of the channel 45, an effect known in fuel-injectionpumps. By turning the piston the position of the control edge is alteredand the amount of delivered fluid is varied.

The pressure of the spring 54 acts on the left side of the piston 50,and the delivery pressure acts on its right side. Equilibrium is reachedwhen both forces are equal. An increase of the delivery pressure movesthe piston 50 with the rack 49 towards the left, changes the position ofthe control edge 42 of piston 40, the port of channel 45 is opened for alonger interval until the equilibrium of piston 50 is restored and at apredetermined head of pressure no fluid is pumped. The head of pressureis determined with the aid of handle 27 turning the screw 57, whichscrew moves the lever 55. The movement of this lever changes the initialpressure of the plate 54 against the spring 53.

The pipe connections to the valve 22 according to Fig. l arediagrammatically shown in Fig. 4. The pipe 21 and pipe 24 are at a rightangle with each other and are connected with valve 22. The pipes 25 and26 are connected with the valve at points opposite of them. The valvemember 57 has two channels 58 and 59, connecting in the shown positionthe pipe 21 with pipe 24 and pipe 25 with pipe 26. After turning themember by 90, the channels connect pipe 21 with pipe 26 and pipe 24 withpipe 25.

The pipe connections according to Fig. 3 are shown in Fig. 5. Pipes 21and 24 are arranged in the same way as above, opposed to pipes 25 and31. Pipe 26 is branched of pipe 25. As the valve member being the sameas in Fig. 4, it is apparent that in the shown position pipe 21 isconnected to pipe 24 and the right end of the cylinder chamber 29, andpipe 31 coming from the left end of the chamber 30 is connected to pipe25. When turning the valve member by 90, the connections are changedover.

The construction of the valve 22 is merely shown by way of example; itmay be arranged, like the pump and the described governor, in any otherknown manner.

At the beginning of a drilling operation, the drilling machine 4 isdisposed at its left final position near the rear end 15 (Fig. 1) of thetubular support 1. The piston 9 is initially situated near the cylinderbase 7 and the piston rod 10 is drawn into the cylinder 6 so that theroller 11 is moved to its right hand end position adjacent to the openend of the cylinder 6. When the drilling machine 4 is switched on thedrill rotates. When the electric motor 17 has been switched on, the pump16 discharges fluid into the pipe 21. From this pipe the fluid flows,with the valve 22 in the position illustrated, via the pipe 24 into thecylinder 6 to the right hand side of the piston 9. Pressure fluidentering cylinder 6, forces the piston 9, together with the piston rodand the roller 11, to the left, thus drawing the right hand portion ofthe chain 13 into the tubular support 1. Consequently, the part of thechain lying above the tubular support 1 travels around the roller 12 toadvance the drilling machine 4 with drill 5 towards the bore hole at apressure dependent upon the pressure adjusted at the pump and theeffective surface area of the piston. In the arrangement illustrated,the path travelled by the drilling machine 4 is twice as long as thestroke of the piston 9.

If the drilling machine 4 is to be retracted again, or if the forwardmotion is to be interrupted, the handle 23 of valve 22 is turned through90. Nevertheless, the pump 16 can still continue to operate since inthis case it discharges to the reservoirs 18 and 19 via the pipes 21 and26. If the drilling machine is moved backwards, then the chain 13 isdrawn out of the tubular support 1. Through this action, the roller 11,piston rod 10 and piston 9 are pushed forwardly into the cylinder 6 andthe liquid contained therein is forced back to the valve casing 22through the pipe 24. From the latter it flows back via the valve boresthrough the pipe 25 to the reservoirs l8 and 19 which, as previouslymentioned, are interconnected.

In the embodiment illustrated in Fig. 3, the previously describedarrangement has been extended so that the drilling machine 4 can beretracted as well as advanced by hydraulic pressure in the followingmanner. A doubleacting piston 28 is inserted in the cylinder 6, thepiston rod 10 of which is sealed at the open end of the cylinder 6 so asto form two working chambers 29 and 30. The chamber 29 is connected withthe valve casing 22 by means of the pipe 24 as in the previous example,and the chamber 30 by means of a pipe 31 which extends from near therear end of the cylinder into the chamber 30.

In this example, the valve casing 22 and its valve are constructed sothat, in the position illustrated, the pipes 21 and 24 as well as thepipes 31 and 25 are connected together and after turning the valvethrough 90 the pipes 21 and 31 and the pipes 24 and 25 are connectedtogether. Apart from the reversing roller or pulley 11, a furtherreversing roller or pulley 32 is secured to the piston rod 10 alongsidethe pulley 11. One end of a second chain 33 is anchored to a bracket 34secured to the inside of support 1 and passes around the roller 32 andover a further reversing roller 35 out of the tubular support 1 to besecured at its other end to the slide 3. The remaining parts of thedevice correspond to those of Fig. 1.

During the forward feed motion of the drilling machine 4, the pressurefluid flows through the pipe 24 into the chamber 29. The piston 28 isthus retracted to the left and with it the piston rod 10; the latteradvances the slide 3 by means of the roller 11 and the chain 13, aspreviously described in connection with Fig. 1. At the same time thechain 33 is pulled out of the tubular sup.- port 1 by the slide 3 inaccordance with its forward feed motion; thus, the chain 33 traversesthe rollers 35 and 32, whereby the latter roller moves with the pistonrod 10 in such a manner that the required length of the chain isreleased. The fluid contained in the chamber 30 flows during thisoperation through the pipes 31 and 25 into the reservoirs 18 and 19.

If the drilling machine 4 is to be retracted, the handle 23 of valve 22is turned through a further right angle so that the pressure fluid nowflows through the pipes 21 and 31 into the chamber 30 and forces thepiston 28 into the cylinder 6. Although the effective surface area ofthe piston 28 is smaller on this side than on the other side owing tothe presence of the piston rod, the return motion proceeds at a speedgreater than the forward motion. The roller 32 when moving in thedrilling direction, with the piston 28 and the piston rod 10,consequently draws the chain 33 into the support 1 via the roller 35;the chain 33 thus moves the slide 3 together with the drilling machine 4towards the rear of the support. The slide 3 in turn draws the chain 13out of the support 1 via the roller 12. This is rendered possible by thefact that the roller 11 moves to a corresponding extent in the drillingdirection.

To obtain a symmetrical construction of the device, one of the chains 13or 33 may be duplicated, one of these chains lying on each side of thecentral plane and symmetrical therewith. The device may be furthersupplemented by means of known supporting and guide members for thechains, piston rod and drill. In both constructions the hydraulic pump16 together with the driving motor 17 and if necessary with the tanks orreservoirs 18 and 19 may be united to form one complete unit which issecured on the support 1.

We claim:

1. A rock drilling machine comprising an elongated tubular body memberhaving inner and outer closed ends, a cylinder positioned axially in thebody member and having an outer closed end disposed adjacent the outerend of the body member and having an inner end spaced from the inner endof the body member, a piston working in said cylinder, a piston rodcarried by the piston and slidably and sealingly extending through theinner end of the cylinder, a pulley rotatably mounted on the inner endof the piston rod and rotatable about an axis transverse to the pistonrod, an elongated flexible connecting member having one end anchoredinside the body member and entrained over said pulley, said outer end ofthe body member having an opening through which the flexible member isslidingly passed, a guide pulley carried by the body member and disposedforwardly of the outer end thereof and rotatable about a fixed axistransverse to the body member, said flexible member being entrained oversaid guide pulley, a drilling machine slidably mounted on the bodymember for guided movement axially thereof, means attaching the otherend of the flexible member to the drilling machine and means carried bythe body member adjacent its inner end for supplying operating fluid tothe cylinder to act on the piston and piston rod to move the drillingmachine outwardly on the body member.

2. A machine as claimed in claim 1, wherein said last means includes ahydraulic pump and motor mounted as a unit on the inner end of the bodymember and having fluid lines connecting with the cylinder and extendingthrough the inner end and a hand control for said lines adjacent saidend.

3. A machine as claimed in claim 2, wherein a second pulley is rotatablymounted on the inner end of the piston rod, a second elongated flexiblemember connected at one end to the drilling machine, a guide pulleyrotatably mounted at the inner end of the body member and over which thesecond flexible member is entrained, means securing the other end of theflexible member inside the body member, said fluid lines being connectedto the References Cited in the file of this patent UNITED STATES PATENTS1,572,371 Smith Feb. 9, 1926 1,844,873 Smith, Sr. Feb. 9, 1932 2,075,706Curtis Mar. 30, 1937

